ifort > Using the Debugging Options > . F90 file

Operation check

CentOS6.5
ifort 14.0.1 20131008

I want to use debug options in Intel Fortran

      implicit none

#ifdef DEBUG      
      print *, "debug"
#else
      print *, "release"   
#endif
      end

The file name should be *.F90. If you try to compile it as a *.f or *.f90, you will end up with a Bad # preprocessor line.

$ifort -DDEBUG sample.F90

If it is, the #ifdef DEBUG becomes effective, and when it is removed, the else part becomes valid. You may also add "#define DEBUG" in the source.

reference